#include <stdio.h>
#include <string.h>


int main(int argc, char *argv[]) {
  char str1[12] = "Hello ";
  char str2[] = "World";

  printf("length: %d\n", strlen(str1));

  strcat(str1, str2);
  printf("%s\n", str1);

  strcpy(str1, str2);
  printf("%s\n", str1);

  printf("%s\n", strchr(str1, 'o'));

  return 0;
}
